Fairchild FAN5607 User Manual

FAN5607 Evaluation Board User Manual
2.4 to 5.5V Input Range
Up to 120mA Output Current (4x30mA)
Adaptive V Adjustment to the Highest
out
Diode Voltage
External Resistor to Set Maximum LED
Current
Enable Input Can have PWM LED Brightness
Control
Short Circuit Protection, Shutdown Mode and
Soft Start
1MHz Operating Frequency
Up to 93% Efficiency
Small 16-lead 4x4mm MLP Package
Description:
The FAN5607 Evaluation Board is a compact circuit including the FAN5607 HMPX in a 4x4 MLP
package and two 4.7uF capacitors which can provide stable input/output current for up to four of
Fairchild's super bright white LEDs. Two 1uF bucket capacitors maintain constant current through the
LEDs in different pump regulator modes. The FAN5607 demo board, a completely assembled and tested
surface mount board, provides easy probe access points to all inputs and outputs so that electrical
characteristics and waveforms can be easily measured.
Where To Begin:
1: Connect Battery (2.4 to 5.5V) and Gnd (0V).
2: Jumper JP5 presets the LED current to 20mA. Use the adjustable resistor POT1 to decrease
the current. (Note: It is not advised to increase current beyond 20mA due to LED limitations)
3: Each LED current can be measured by removing jumpers JP1 through JP4 respectfully and
applying a current meter. Observe that the LED current is constant regardless of Battery input
voltage and that current is not affected by varying numbers of LEDs. Observe that the supply
current changes in steps when the battery voltage reaches the threshold of mode changes.
(Note: Replacing the provided LEDs with other types can affect the input voltage threshold
values where transition modes occur)
4: Adding resistor R1 by removing jumper JP6 reduces battery voltage ripple.
5: To verify supply current in "ON" and "OFF" modes, observe that in shutdown mode, supply
current will drop below 1uA at Battery input.
6: To verify PWM dimming, remove ENABLE jumper and apply a PWM signal of 100Hz to ON
(pin 2). Observe that the average LED current is directly proportional to the duty cycle.
7: To measure clock frequency, connect scope probe to bucket capacitors C1+, C1-, C2+
and C2-
8: Observe that the circuit is protected from open load conditions by verifying the output
voltage Vout < 6V.
©2005 Fairchild Semiconductor Corporation
FAN5607 Version 1.0
Figure 1: FAN5607 HMPX
1
July 2005
www.fairchildsemi.com